The numerical method on a double-channel sewage pump was studied. while the corresponding experimental result was also provided. On this basis. the influence of wall roughness on the pump performance was deeply studied. https://www.roneverhart.com/Western-Digital-Ultrastar-DC-HC550-WUH721816ALE6L0-0F38460-16TB-7-2K-RPM-SATA-6Gb-s-512e-ISE-3-5in-Hard-Drive/